Christmas Star NASA
Credit: NASA/ Bill Ingalls

Biblical Star of Bethlehem appears in sky ahead of Christmas for first time in 800 years

Christian Winthrop·
LocalThe BuzzThe Net

Jupiter and Saturn lined up last night and appeared as one bright shining star for the first time in 800 years, and won’t occur again until 2080. Many refer to it as the Christmas Star. It’s also known as the Star of Bethlehem, believed to have guided the wise men to the birth of Christ. The Book of Matthew describes how these three wise men saw the new star as a sign of the birth of the King of the Jews.

EarthSky.org says the last observable Jupiter-Saturn conjunction that was this close occurred nearly 800 years ago in 1226.

In 1610, Italian astronomer Galileo Galilei pointed his telescope to the night sky, discovering the four moons of Jupiter – Io, Europa, Ganymede, and Callisto. In that same year, Galileo also discovered a strange oval surrounding Saturn, which later observations determined to be its rings. These discoveries changed how people understood the far reaches of our solar system.

Thirteen years later, in 1623, the solar system’s two giant planets, Jupiter and Saturn, traveled together across the sky. Jupiter caught up to and passed Saturn, in an astronomical event known as a “Great Conjunction.”

“You can imagine the solar system to be a racetrack, with each of the planets as a runner in their own lane and the Earth toward the center of the stadium,” said Henry Throop, astronomer in the Planetary Science Division at NASA Headquarters in Washington. “From our vantage point, we’ll be able to be to see Jupiter on the inside lane, approaching Saturn all month and finally overtaking it on December 21.”

The planets regularly appear to pass each other in the solar system, with the positions of Jupiter and Saturn being aligned in the sky about once every 20 years.

What made this year’s spectacle so rare, then? It’s been nearly 400 years since the planets passed this close to each other in the sky, and nearly 800 years since the alignment of Saturn and Jupiter occurred at night, allowing nearly everyone around the world to witness this “great conjunction.”

The closest alignment will appear just a tenth of a degree apart and last for a few days. On the 21st, they will appear so close that a pinkie finger at arm’s length will easily cover both planets in the sky. The planets will be easy to see with the unaided eye by looking toward the southwest just after sunset.

From our vantage point on Earth the huge gas giants will appear very close together, but they will remain hundreds of millions of miles apart in space. And while the conjunction is happening on the same day as the winter solstice, the timing is merely a coincidence, based on the orbits of the planets and the tilt of the Earth.

“Conjunctions like this could happen on any day of the year, depending on where the planets are in their orbits,” said Throop. “The date of the conjunction is determined by the positions of Jupiter, Saturn, and the Earth in their paths around the Sun, while the date of the solstice is determined by the tilt of Earth’s axis. The solstice is the longest night of the year, so this rare coincidence will give people a great chance to go outside and see the solar system.”

PHOTOS:

 

 
 
 
 
 
View this post on Instagram
 
 
 
 
 
 
 
 
 
 
 

 

A post shared by Lars Leber Photography (@larsleberphotography)

 

 
 
 
 
 
View this post on Instagram
 
 
 
 
 
 
 
 
 
 
 

 

A post shared by Good Astronomy (@goodastronomy)